I'm working on a web application where users submit a request, are redirected to a page that says something like "processing, please don't hit the back button", and after a few seconds, are redirected to the final result.
If they do try to go back to the form while we're processing, we have code to handle that, but I'd like to help them understand that we really are working on their request.
The "please wait" page currently has a fairly generic "spinning ball" kind of graphic. Maybe a progress bar would be better? In reality, we can't predict exactly how long it will take, but we could pretend if it would help them understand that we're working on it.
How can I encourage users to be patient and not use their back button while their request is being processed?